Transfer medium for producing scratch and smudge resistant marks

ABSTRACT

A TRANSFER MEDIUM COMPRISING A BASE HAVING A TRANSFERABLE COATING COMPOSITION THEREON. THE TRANSFERABLE COMPOSITION COMPRISES ABOUT 3 TO 40 PERCENT BY WEIGHT OF POLYSILOXANE RUBBER GUM; ABOUT 3 TO 40 PERCENT BY WEIGHT OF A POLYSILOXANE RESIN; ABOUT 15 TO 70 PERCENT BY WEIGHT OF A THERMOPLASTIC AMINOTRIAZINE-SULFONAMIDE-ALDEHYDE RESIN; AND ABOUT 1 TO 45 PERCENT BY WEIGHT OF A SENSIBLE MATERIAL. THE OUTER SURFACE OF THE COATING COMPOSITION HAS A THIN COATING OF WAX.

United States Patent 3,689,316 TRANSFER MEDIUM FOR PRODUCING SCRATCH ANDSMUDGE RESISTANT MARKS Charles T. Fellows, Kettering, Stanley R.Hermann,

Xenia, and Norman C. Hochwalt, Dayton, Ohio, assignors to The NationalCash Register Company, Dayton, Ohio No Drawing. Continuation-impart ofabandoned application Ser. No. 54,856, July 14, 1970. This applicationOct. 29, 1970, Ser. No. 85,312

Int. Cl. B41m 5/10 US. Cl. 117-234 13 Claims ABSTRACT OF THE DISCLOSUREA transfer medium comprising a base having a transferable coatingcomposition thereon. The transferable composition comprises about 3 to40 percent by weight of polysiloxane rubber gum; about 3 to 40 percentby weight of a polysiloxane resin; about 15 to 70 percent by weight of athermoplastic aminotriazinesulfonamide-aldehyde resin; and about 1 to 45percent by Weight of a sensible material. The outer surface of thecoating composition has a thin coating of wax.

This application is a continuation-in-part of US. patent applicationSer. No. 54,856 filed July 14, 1970, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to transfer media andto a process for making the same. More particularly, this inventionrelates to transfer media, having transferable coating compositionsthereon, which are suitable for applications requiring transfer of thecoating composition from the transfer medium to a recording medium.Transfer pressure is applied by means of pressure or by means ofpressure and heat such as the impact of type or pressure from othermarking instruments in selected areas, either to the back of a transfermedium which has a transferable coating composition thereon or to theback of a recording medium to cause break-away of the coatingcomposition from the transfer medium and adherence of such broken-awaycoating composition to the recording medium.

Transfer media such as carbon paper and typewriter ribbons have, ofcourse, been known and used for many years. Lately, however, the placingof various types of printed marks on recording media to be handled andsensed by data processing equipment has become a matter of increasinginterest and special transfer sheets and printing ribbons have beendeveloped to meet the requirements of such data processing equipment.

One of the greatest problems encountered with marks printed on recordingmedia is the great tendency for the printed marks to scratch or smudge.The marks printed on the recording medium usually become scratched orsmudged when the printed medium is passed through ordinary commercialtransactions and when the printed medium is passed through dataprocessing equipment. This problem of scratching and smudging isencountered even with some of the most recently developed transfermedia. When this scratching or smudging occurs, the reliability withwhich the true mark can be automatically sensed is severely impairedeven though the impairment may sometimes be comparatively slight byvisual standards.

The present invention provides a transfer medium which is capable ofproducing suitable printed marks on a recording medium which havesufiicient resistance to scratching and smudging when the printed mediumis passed through ordinary commercial transactions and when the printedmedium is processed through data processing equipment so that theprinted marks do not sustain any change sufiicient to affect theaccuracy of the sensing operation. For very demanding circumstances,heat settin of the printed marks produces superior scratch and smudgeresistance. T

The present invention provides transfer media, having coloredtransferable coating compositions thereon, which may be used in theprinting of colored code bars on recording media such as paperboardmarking tags used by merchandising institutions to identify inventory.Such color-coded tags have resulted in a major breakthrough in machinereadable media technology. In a typical system, white paperboard tagsare printed with font which is readable by humans and are encoded orprinted with different colored bars by a color-coded tag printer whichare readable by an optical scanning device known as a color-coded tagreader. The colored printed bars may be separated thereby allowing thewhite background of the paper to form a third colored bar. The tagitself offers many business system advantages which include attachmentmethods, base stock variety, information capacity and flexibility. 'Ihecolor-coded tag serves as a medium to transfer data between thecolor-coded tag printer, which encodes data contained in a sourcedocument onto the tag, and the color-coded tag reader which enters thecolor-coded data into the business system usually at the point of sale.The color-coded tag reader utilizes optical scanning tosense anddistinguish the different colored bars which have been encoded on thetag by the tag printer in a binary pattern and to convey the encodedinformation contained in the bars to the business system.

In a color-coded tag system as described above, it is very importantthat the different colored bars which are encoded on the tag have a highresistance to scratching and smudging so that the information containedin the bars can be correctly read by the optical scanning device of thecolor-coded tag reader.

The present invention also provides transfer media, having improvedtransferable coating compositions, which may be used in the encoding orprinting of paper records, such as checks, bank deposit slips, creditcharge slips and the like with magnetic symbols which can be recognizedby electronic accounting equipment or which may be used as one-timecarbon ribbons or papers.

It will be readily apparent that the principles of the present inventioncan be applied whether the transfer medium is arranged to deposit markssuitable for sensing visually, by optical means, by photoelectric means,by magnetic means, by electroconductive means, or by any other meanssensitive to a special material in the coating.

PRIOR ART The present invention comprises a transfer medium having atransferable coating composition thereon. The transferable coatingcomposition comprises a polysiloxane rubber gum, a polysiloxane resin,an aminotriazine-sulfonamide-formaldehyde resin and a sensible material.The outer surface of the coating composition has a thin coating of wax.The transfer medium of the present invention produces encoded or printedmarks on a recording medium which possess improved scratch and smudgeresistant properties.

The most pertinent prior art is found in the following patents whichdisclose transfer media which produce printed marks on recording mediaby means of pressure such as the impact of type or pressure from othermarking instruments. U.S. Pat. 2,984,582 discloses a transfer mediumhaving a porous, thermoplastic resin layer containing a transferableink. The ink is released by the resin layer onto a recording mediumwithout transfer of the resin layer onto the recording medium. U.S.Pats. 2,671,734; 2,822,288; 3,337,361 and 3,340,086 disclose transfermedia which produce encoded or printed marks on a recording medium. Noneof these patents disclose the transfer medium having the transfercoating composition of the present invention. U.S. Pat. 3,062,676discloses a transfer medium having a coating composition which is formedof a plurality of coatings. The coatings are transferred to a recordingmedium thereby producing encoded or printed marks on the medium whichpossess good smudge resistant properties. U.S. Pat. 3,087,832 disclosesa transfer medium having a coating composition which comprises amagnetic pigment mixed in a silicone resin and a silicone rubber bindersystem. The coating composition has a top coating of wax which aids inthe adherence of the magnetic transfer coating to a recording mediumupon transfer thereto. US. Pat. 3,375,125 discloses a transfer mediumhaving a coating composition which comprises ethyl cellulose, a resinbinder, mineral oil, a wax and a pigment. The coating composition istransferred to a recording medium thereby producing encoded or printedmarks on the recording medium which possess good smudge resistantproperties.

The prior art does not disclose the novel transfer medium of the presentinvention which produces encoded or printed marks on a recording mediumpossessing improved scratch and smudge resistant properties.

SUMMARY OF THE INVENTION In accordance with the present invention, thereis provided a transfer medium comprising a base having a transferablecoating composition thereon. The transferable coating compositioncomprises about 3 to 40, preferably about 15 to 25, percent by weight ofa polysiloxane rubber gum having a molecular weight ranging from about200,- 000 to 1,000,000, preferably about 300,000 to 700,000; about 3 to40, preferably about 15 to 25, percent by weight of a polysiloxane resinhaving a molecular weight ranging from about 300 to 100,000; about 15 to70, preferably about 50 to 65, percent by weight of a thermoplasticaminotriazine-sulfonamide-aldehyde resin and about 1 to 45, preferablyabout 2 to 20, percent by weight of a sensible material. The abovepercents by weight are based on the total weight of the transferablecoating composition.

The outer surface of the coating composition has a very thin coating ofwax, for example, about 0.05 to 0.15 mil, to aid in the adherence of thetransferred coating composition to the receiving medium. The wax has amelting point of about 140 to 220, preferably about 155 to 200 F. and aneedle penetration of about 0.5 to 10, preferably about 1 to 9.

In further accordance with the present invention, the transfer medium ofthe present invention is produced by a process which comprises applyingthe above named components of the coating composition to a suitable baseby means of a volatile organic solvent carrier. The solvented coatingcomposition is spread uniformly over the base and the volatile organicsolvent carrier is then allowed to evaporate thereby leaving atransferable coating composition deposited on the base. The outersurface of the coating composition which is a thin coating of wax can beapplied from a hot melt.

DETAILED DESCRIPTION OF THE INVENTION The polysiloxane rubber gum canhave a molecular weight ranging from about 200,000 to 1,000,000,preferably about 300,000 to 700,000. The polysiloxane rubber gum can besubstituted with alkyl groups such as methyl or ethyl, or aryl groupssuch as phenyl or tolyl, or alkenyl groups such as vinyl or propenyl,and the like, or mixtures thereof along the polysiloxane chain.

The polysiloxane resin can have a molecular weight ranging from about300 to 100,000. The polysiloxane resin can be substituted with alkylgroups such as methyl or ethyl, or aryl groups such as phenyl or tolyl,or alkenyl groups such as vinyl or propenyl, and the like, or mixturesthereof amid the polysiloxane cross-linked structure.

The thermoplastic aminotriazine-sulfonamide-aldehyde resin used in thepresent invention is a co-condensation product of a cyclicaminotriazine, an aromatic monosulfonamide and an aldehyde such asformaldehyde. The thermoplastic resin should preferably be completelycondensed.

The thermoplastic aminotriazine-sulfonamide-aldehyde resin may beprepared from an aromatic monosulfonamide having two reactive amidehydrogens, a cyclic aminotriazine having at least two primary aminogroups and an aldehyde such as formaldehyde or paraformaldehyde. Ifdesired, either or both of the first-mentioned components may beseparately reacted with the aldehyde to form a thermoplasticsulfonamide-aldehyde resin or a B-stage partially condensedaminotriazine-aldehyde resin, respectively, before being co-condensed.The aromatic sulfonamide may comprise toluene sulfonamide, for example,orthoor para-toluene sulfonamide or mixtures thereof, benzenesulfonamides, or the alkyl derivatives of such sulfonamides, and thelike, in which the sulfonamido group is attached directly to thearomatic nucleus through the sulfur atom.

The cyclic aminotriazine compound may comprise a compound having atleast two amino groups as represented by the following formula:

wherein R is hydrogen, alkyl containing 1 to about 8 carbon atoms, aryl,aralkyl, amino, and the like.

The following are typical aminotriazine compounds within the aboveformula:

2,4-diamino-1,3,5-triazine 2-methyl-4,6-diamino-l,3,5-triazine2(3-hydroxy butyl)4,6-diamino-1,3,5-triazine2-heptyl-4,6-diamino-1,3,5-triazine 2-phenyl-4,6-diamino-1,3,5-triazine2-benzyl-4,6-diamino-1,3,5-triazine 2,4,6-triamino-1,3,5-triazine(melamine) In place of melamine as the aminotriazine compound, one canuse methyl melamine or other alkyl derivatives of melamine, that is,n-alkyl melamines, such as the monoor dialkyl derivatives where thealkyl group may be methyl, ethyl, propyl, butyl, and the like, up toabout 8 carbon atoms.

Also, the B-stage methylol aminotriazine resin can be modified byforming the alkyl ether of the methylol aminotriazine. For example, thiscan be done by taking an A- stage methylol aminotriazine, that is, thetri-, tetraor pentamethylol aminotriazine, and then converting to the B-stage resin in the presence of an alkanol such as methanol, ethanol,propanol, butanol, and similar alkanols containing up to about 8 carbonatoms. When using methanol, the resin would be the monoor dimethyl etherof tri-, tetraor pentamethylol aminotriazine, in partially condensedform. Also, alkanol derivatives of the aminotriazine in which the alkylgroup contains more than about 3 carbon atoms may be formed during thecourse of the co-condensation reaction by introducing the aminotriazinein a solution of an alcohol such as butanol. It will be noted that theaminotriazine reacts as an amide rather than as an amine.

The relative quantities of the materials to be co-condensed are criticalonly to the extent that sufiicient aldehyde should be used to produce acompletely condensed product; if too large a quantity of theaminotriazine is used, the final product will be a thermosettingproduct, which is not desired; and if too small a quantity of theaminotriazine is used, the softening point of the product will differonly slightly from the softening point of the sulfonamide-formaldehyderesin and may not have insolubility in the desired solvents. Also, theamount of the sulfonamide is dependent upon the number of primary aminogroups in the aminotriazine. For example, it is preferred to use aboutthree times (on a molar basis) as much as the sulfonamide as theaminotriazine When the aminotriazine contains two amino groups, andabout five times (on a molar basis) as much sulfonamide when theaminotriazine contains three amino groups. In other words, theaminotriazine or B-stage aldehyde-aminotriazine resin is preferably fromabout 20 to 33 mol percentage of the amount of the monosulfonamide orthe aldehyde-monosulfonamide resin, although the former may be as greatas about 50 mol percent and as little as about 17 mol percent of thelatter.

Generally, when preparing the alkanol modified resin, it is necessary touse additional quantities of formaldehyde over and above that requiredfor the alkanol modification so as to provide for subsequentco-condensation with the sulfonamide-formaldehyde resin. The B-stageaminotriazine-formaldehyde resin, that is, the methylol aminotriazine,must have at least two methylol groups and preferably three such groupsin order to successfully carry out the subsequent co-condensation withthe sulfonamide resin.

The thermoplastic resin may be prepared using as reactants eitherformaldehyde or its polymer, paraformal: dehyde, which polymer has thegeneral formula where n is 6 or greater. This monomer and its polymershould be distinguished from polyaldehydes such as glyoxal containing aplurality of aldehyde groups in a stable molecule.

Typical modes of preparation of the thermoplasticaminotriazine-'sulfonamide-aldehyde resin used in the present inventionare found in US. Pat. 2,938,873 in Examples 1 through 25. These examplesare incorporated herein as a part of this specification.

In a preferred embodiment, the thermoplasticaminotriazine-sulfonamide-aldehyde resin is a co-condensation product ofa melamine, an aromatic sulfonamide and an aldehyde such asformaldehyde. The thermoplastic resin should preferably be completelycondensed. The thermoplastic melamine-sulfonamide-aldehyde resin may beprepared from an aromatic mono-sulfonamide having two reactivehydrogens, that is, two reactive amide hydrogens, a melamine or amelamine derivative having at least two functional amide groups andformaldehyde or paraformaldehyde. If desired, either or both of thefirst-mentioned components may be separately reacted with formaldehydeto a form a thermoplastic sulfonamide-aldehyde resin or a B-stagepartially condensed melamine-aldehyde resin, respectively, before beingco-condensed. The aromatic sulfonamide may comprise a mixture oforthoand paratoluene sulfonamides, benzene sulfonamide or the alkylderivative thereof or a toluene sulfonamide wherein the sulfonamidogroup is attached directly to the aromatic nucleus through the sulfuratom.

The B-stage partially condensed melamine-aldehyde resin (methylolmelamine resin) is the water soluble, thermofusible reaction product ofmelamine and formaldehyde or paraformaldehyde. In place of melamine, onecan use the methyl melamine or other alkyl derivatives of melamine suchas the monoor dialkyl derivatives where the alkyl group may be methyl,ethyl, propyl, butyl Or the like.

Also, the B-stage melamine-aldehyde resin can be modified by forming the:alkyl ether of the melamine-aldehyde resin. This can be done by takingan A-stage melamine-aldehyde resin, that is, the tri-, tetraorpentamethylol melamine resin, and then converting it to the B-stageresin in the presence of an alkanol such as methanol, ethanol, propanol,butanol or the like. When using methanol, the modified B-stage resinwould be the mono-, dior trimethyl ether of tri-, tetraor pentamethylolmelamine in partially condensed form.

The relative quantities of the materials to be co-condensed are criticalonly to the extent that more than about 20 percent by weight of theunmodified melamine-aldehyde B-stage resin in the final product willproduce a thermosetting product, which is not desired, and, if too smalla quantity of the melamine resin is used, the softening point of theproduct will differ only slightly from the softening point of thearomatic sulfonamide-aldehyde resin. In other words, the amount byweight of the sulfonamide-aldehyde resin should be at least four timesthe amount of the unmodified B-stage melamine-aldehyde resin. When theunmodified melamine-aldehyde B-stage resin is employed, it is preferredto use about 16 percent thereof based on the weight of the finalco-condensed resin, that is, about five times as much of thesulfonamidealdehyde resin as the unmodified B-stage melamine-aldehyderesin. When the melamine derivatives or the modified B-stage melamineresins are used, greater relative quantities can be employed up to about25 to 35 percent by weight of the final product, that is, up to about 50percent by weight of the sulfonamide-aldehyde resin. Generally, whenemploy-ing a melamine derivative to form the B- stage partiallycondensed resin or when preparing the alkanol modified melamine resin,it is desirable to use greater quantities of the aldehyde so as toprovide additional methylol groups for subsequent co-condensation withthe sulfonamide-aldehyde resin. The B-stage melamine-aldehyde resin,that is, the methylol melamine resin, must have at least two methylolgroups and preferably three or four such groups in order to successfullycarry out the subsequent co-condensation with the sulfonamide resin.

The various melamine derivatives having at least two functional amidegroups, which are useful substitutes for melamine for the purposes ofthe present invention, include all of such derivatives mentioned in theforegoing discussion. Stated most simply, by way of summary, theyinclude alkyl melamines having preferably no more than one alkylsubstituted amido nitrogen and monohydric alkanol modified methylol andalkyl methylol melamines.

The melamine-sulfonamide-aldehyde resin can be prepared using eitherformaldehyde or its polymer, paraformaldehyde, as reactants. Thismonomer and its polymer, wherein the same atoms are present in the sameproportion, should be distinguished from isomerides of formaldehyde suchdiformaldehyde which contains a plurality of aldehyde groups in a stablemolecule.

Typical modes of preparation of the thermoplasticmelamine-sulfonamide-aldehyde resin used in the present invention arefound in U.S. Pat. 2,809,954, in Examples 1 through'15. These examplesare incorporated herein as a part of this specification.

The aminotriazine-sulfonamide-aldehyde resin has a higher softeningpoint than the well-known sulfonamidealdehyde resins and has somecharacteristics which are in no way similar to the completely condensedaminotriazinealdehyde resins and other characteristics which are in noway similar to the thermoplastic sulfonamide-aldehyde resins. Theaminotriazine-sulfonamide-aldehyde resin not only has a higher meltingpoint than the sulfonamide-aldehyde resins, but it will release solventsmore rapidly than such resins and does not exhibit cold flow at roomtemperature as do the sulfonamide-aldehyde resins. On the other hand,the aminotriazine-sulfonamide-aldehyde resin, unlike theaminotriazine-aldehyde resin, is soluble in certain solvents and isthermoplastic. The overall character of theaminotriazine-sulfonamide-aldehyde resin makes it especially suitablefor the manufacture of pigments. For example, theaminotriazine-sulfonamide-aldehyde resin can be highly colored and, eventhough thermoplastic, can be readily ground to a finely dividedcondition at temperatures below about 100 C. Most thermoplastic resinswill either soften at the temperatures encountered during grinding orwill tend to ball up or agglomerate, even at temperatures below thesoftening point, probably due to cold flow under the pressure of thegrinding elements. The aminotriazine-sulfonamide-aldehyde resin isbrittle and friable below its softening point and is not hornlike andtough as are most thermoplastic resins. Theaminotriazine-sulfonamide-aldehyde resin is insoluble in many commonvehicles and can therefore be suspended in such vehicles withoutcoalescence or agglomeration.

The wax used in the present invention is a wax having a melting pointranging between about 140 to 220, preferably about 155 to 200 F. asdetermined by ASTM D127. Suitable waxes include natural waxes such ascarnauba, montan and the like and mixtures thereof; synthetic waxes suchas hydrogenated, amide, chlorinated, alkene or olefinic, miscellaneousand the like and mixtures thereof; and petroleum waxes such asmicrocrystalline, parafiin and the like and mixtures thereof.

The term wax, as used herein, defines a class of waxes which ischaracterized by a particular degree of hardness as determined by aneedle penetration test ASTM D-1321. The needle penetration testmeasures the depth to which a weighted needle penetrates a sample ofwax. In the needle penetration test, a wax sample is melted by heatingit to about 30 F. above its melting point and is then solidified bycooling to 77 F. The hardness of the wax is measured with a penetrometerwhereby a standard needle, under a load of 100 grams, is applied to thewax sample for 5 seconds. The depth to which the needle penetrates thewax during the 5 second time interval is measured in tenths of amillimeter. If the needle penetrates the wax to a depth of 0.2millimeter, the hardness rating of the wax is 2. If the needlepenetrates the wax to a depth of 0.8 millimeter, the rating of the waxis 8, and so forth. The waxes which can be used according to thisinvention are those which have a rating from about 0.5 to 10, preferablyabout 1 to 9. The wax can be an animal, mineral, petroleum, synthetic orvegetable wax or a mixture thereof so long as the wax is stable, can bemeltable, emulsifiable or solvent dispersible, has the required degreeof hardness and has the above indicated melting point range.

The sensible material used in the present invention can be any materialwhich is capable of being sensed visually, by optical means, byphotoelectric means, by magnetic means, by electroconductive means or byany other means sensitive to the sensible material. The sensiblematerial can be an inorganic or organic material such as a coloringmaterial, namely, a dye or a pigment, a magnetic material or any othermaterial capable of being sensed and which is compatible with thecoating composition.

Suitable sensible materials include phthalocyanine dyes such asMonostral Green B (color index No. 74260), Monastral Green G (colorindex No. 74260), Sherwood Green (color index No. 42000) and TropicalBrilliant Green (color index No. 42040); fluorescent rhodamine orxanthene dyes such as rhodamine B Extra (color index No. 45170),rhodamine GDN Extra (color index No. 45160), xylene red (color index No.45100), rhodamine 5G (color index No. 45105), rhodamine G (color indexNo. 45150) and rhodamine 2B (color index No. 45151); fluorescentnaphthalimide dyes such as brilliant yellow 6G (color index No. 29000)which has the formula 4-amino- 1,8-naphthal-2',4-dimethyl phenylimide,other fluorescent naphthalimide dyes such as(4-n-butyl-amino)-1,8-naphthal-n butyl imide and 4- amino-1, 8-naphthalp-xenyl imide; other dyes or pigments such as malachite green (colorindex No. 42000); cadmium primrose (color index No. 77199), chromeyellow (color index No. 77600), Ultramarine Blue (color index No.77007), Phthalocyanine Blue (color index No. 74160), Lake Red C (colorindex No. 15585), Sodium Lithol Red (color index No. 15630); titaniumdioxide and zinc oxide; magnetic metal oxides such as iron oxide, cobaltoxide and nickel oxide; finely divided metals and alloys such as bronze,stainless steel, iron, cobalt, nickel and chrome; and miscellaneouscoloring materials such as carbon black, conductive carbon and charcoal.

As an example of sensible material which is not normally visible, butcan be detected, a small amount of a material such as4-methyl-7-diethy1amino coumarin will not color a coating compositionwhen it is exposed to ordinary light but will produce a bright bluecolor when the coating composition is exposed to ultraviolet light.

The sensible material can include any luminescent, fluorescent orphosphorescent material, either organic or inorganic, or any materialswhich are partially visible or substantially invisible, in normal orordinary light, and which become visible or emit energy when exposed tolight or energy difiering in kind or wave length from that emitted bythe luminescent material. The term luminescent material is intended toinclude and denote both fluorescent materials, which are activated byenergy of shorter wave length and emit energy of longer wave length, andphosphorescent materials which continue to emit light or energy afterexcitation is discontinued.

The above-named sensible materials constitute only a fraction of themany different sensible materials that can be used in the presentinvention and are not to be construed as limiting the scope of thesuitable sensible materials that can be used in the present invention.Any of the above-named sensible materials can be used alone or incombination with each other or in combination with other suitablesensible materials not specifically named above. The sensible materialneed only be suitable for the sensing required, have a high resistanceto scratching and smudging when the coating composition is transferredonto the recording medium and be compatible with the coatingcomposition.

The sensible material can be chosen so that the transferred coatingcomposition will reflect a certain amount of light within a particularwave length. For example, a black sensible material can be chosen sothat the transferred coating composition has a diffused reflectance ofless than 15 percent of light between a wave length of 600 and 1200nanometers and a green sensible material can be chosen so that thetransferred coating composition has a diffused reflectance of less thanpercent of light between a wave length of 600 to 750 nanometers, 50percent of light between a wave length of about 820 and 870 nanometers,and greater than 80 percent of light between a wave length of 900 and1200 nanometers. The wave length of light between 600 and 1200nanometers is within the visible and the near infra-red spectrum. Thechoosing of a sensible material for such optical properties is useful inan optical sensing device.

The base to which the transferable coating composition is applied can bea thin material such as a film, web, sheet, ribbon, fabric or the like.The preferred base is a film of polyethylene terephthalate, however,other bases can be used. For example, cellulosic materials, paper,cellophane, nylon, rubber hydrochloride, polyethylene, polypropylene andthe like are acceptable bases when used in the form of a film, web,sheet, ribbon, fabric or the like. The base should have a thickness ofabout 0.2 to 2, preferably of about 0.3 to 0.8 mil. The base should besuch that the transferable coating composition adheres to the base in aproper manner prior to transfer of the coating composition to therecording medium and the transferable coating composition is releasedfrom the base in a proper manner upon transfer. The base should belimited in thickness to permit a full realization of the capability ofthe transferable coating composition to deposit marks having sharp,clear edge definition on a recording medium. The base should alsopossess uniform tensile and other physical properties to insure uniformtransfer of the coating composition onto a recording medium.

The transferable coating composition containing the sensible materialcan be applied to the base in the following manner to produce thetransfer medium of the present invention. The polysiloxane rubber gumand the polysiloxane resin and the volatile organic solvent carrier canbe mixed with constant stirring until a composition having a uniformconsistency is obtained. The aminotriazine-sulfonamide-aldehyde resinand the sensible material can then be added to the compositioncomprising the polysiloxane rubber gum, the polysiloxane resin and thevolatile organic solvent with constant stirring until a compositionhaving a uniform consistency is obtained. About 500 to 100, preferablyabout 300 to 150, parts of organic solvent is usually used per 100 partsof polysiloxane rubber gum, polysiloxane resin,aminotriazine-sulfonamide-aldehyde resin and sensible material used.However, the ratio of solvent to the aforementioned components isusually not particularly crltical. It is preferred that theaminotriazine-sulfonamidealdehyde resin be insoluble or at most onlypartially soluble in the volatile organic solvent so that theaminotriazinesulfonamide-aldehyde resin is dispersed in the solventedcoating composition. The solvented coating composition is then milleduntil the composition is homogeneous and the particle size of theaminotriazine-sulfonamide-aldehyde resin is reduced to about 3 microns.The sensible material can be added separately to the coating compositionor the sensrble material can be mixed, dispersed or dissolved in theaminotriazine-sulfonamide-aldehyde resin and then added to the coatingcomposition. The sensible material can be added to theaminotriazine-sulfonamide-aldehyde resin during its production or afterits production. Specific details for adding the sensible material to theresin are contained in U.S. Pat. 2,809,954 in Examples 6 through 15 andin U.S. Pat. 2,938,873 in Examples 9 through 25. These examples areincorporated herein as a part of this specification.

The transferable coating composition can be applied to the base by rollcoating, knife coating or by a similar means. The volatile organicsolvent can be evaporated at ambient temperature or can be evaporated bythe application of gentle heat thereby leaving a transferable coatingcomposition having a thickness of about 0.1 to 0.4, preferably about0.15 to 0.3, mil deposited on the base.

Suitable volatile organic solvent carriers for the coating compositioninclude aliphatic and aromatic hydrocarbon solvents such as mineralspirits, naphtha, xylene, toluene and mixtures thereof. Other suitableorganic solvents include isopropyl alcohol, isobutyl alcohol, 3heptanol, isoamyl acetate, ethyl amyl ketone, diisobutyl ketone, carbontetrachloride, carbon disulfide and mixtures thereof. The polysiloxanerubber gum and the polysiloxane resin should be soluble or at leastpartially soluble in the 'volatile organic solvent so that there is aco-mingling of the polysiloxane rubber gum and the polysiloxane resin.One of the above suggested solvents or a mixture thereof can be selectedwith this criteria in mind.

The wax coating on the transferable coating composition can be appliedto the coating composition by roll coating, knife coating or by asimilar means from a hot melt, emulsion or solvent dispersion of thewax.

The above process for producing the transfer medium of the presentinvention is only illustrative and can be varied within reasonablelimits to produce the transfer medium of the present invention.

PREFERRED EMBODIMENTS The following examples illustrate the presentinvention and modes of carrying out the invention.

Example 1 A typical thermoplastic aminotriazine-sulfonamide-aldehyderesin is prepared in the following manner. 360 parts by weight of amixture of orthoand para-toluene sulfonamide-formaldehyde resins aremelted at a temperature of 60 to 70 C. and are then heated to atemperature of 125 C. At this temperature, 78.4 parts by weight ofB-stage unmodified melamine-formaldehyde resin are added and dissolvedtherein and heating is continued. The reaction mixture becomes clear ata temperature of about 150 C. and heating is continued up to atemperature of 170 C. and held there for about 10 minutes. Upon cooling,the cocondensed resin begins to solidify at a temperature of about 115C. The completely condensed product is a clear water-white resin which,below a temperature of about C., is brittle, friable and is easilyground in a micropulverizer or by wet ball milling into a finely dividedpowder having a particle size of about 4 microns. The completelycondensed resin has a softening point at a temperature of about C.Thermoplastic aminotriazine-sulfonamide-aldehyde resins havingsubstantially the same physical properties as the above prepared resinare prepared in accordance with Examples 2 through 6 of U.S. Pat.2,809,- 954 and Examples 2 through 9 of U.S. Pat. 2,938,873. Theseexamples are incorporated herein as a part of this specification.

A sensible material is incorporated in any of the foregoing clear resinshaving substantially the same physical properties when the reactionmixture reaches a temperature of between and C. while the reactionmixture is heated up to a temperature of between to C. or by melting thefinished resin at a temperature between 130 to 160 C. and adding thesensible material to the melt, solidifying and regrinding the resin.Where applicable, the solidified resin and the sensible material may bedissolved in a ketone or an ester solvent, the solvent evaporated andthe composition of sensible material and resin ground to a fine powder.About 1 to 50 parts by weight of the sensible material is added to 100parts by weight of the resin depending upon the properties desired inthe coating composition of the transfer medium.

Example 2 Green and black transfer media, that is, printing ribbons,were prepared in the following manner using solvented coatingcompositions described in the following table.

SOLVENTED COATING COMPOSITIONS Parts by weight of 1 Marketed by theGeneral Electric Company, Waterford, N.Y., USA. under the tradedesignation of SE-76. This is a dimethyl polysiloxane rubber gum whichhas an average molecular weight of about 340,000 to 390,000 and aWilliams Plasticity N o. of 75 to 120 as measured in accordance withAS'IM D-926 at room temperature for three minutes.

9 Marketed by the Dow Corning Corporation, Midland, Mich., U.S.A. underthe trade designation of DO-2l06 resin. This resin is a hydroxy curing,methyl phenyl resin having an OH content of about 1 percent and amolecular weight distribution ranging from about 300 to 100,000. Thisresin has a silicone solids content of 59 percent by weight in tolueneand a viscosity of 20 to 50 centipoises at 77 F. This resin is describedin Dow Corning Bulletin 07-321 dated June 1969 and 11.3. Pat. 2,718,483.

3 Marketed by the Day-Glo Color Corp., Cleveland, Ohio, U.S.A. under thetrademark of DAY-GLO Fluorescent Pigment Horizon Blue A-19. Thismaterial comprises about 96 percent weight of a thermoplasticmelamine-sulfonamide-iormaldehyde resin prepared in accordance withExample 1, about 3 percent by weight of a daylight fluorescent blue dyeand about 1 percent by weight of a phthalocyanine blue toner. Thismaterial has a minimum luminance factor of 17 percent, a minimum purityof 65 percent and a dominant wavelength of 475 to 480 millimicrons ornanometers determined in accordance with the daylight fluorescent colorspecification system described on pages 23 through 25 of the Day-G10Color Corp. Technical Booklet No. l170-A.

4 Marketed by the Day-G10 Color Corp., Cleveland, Ohio, U.S.A. under thetrademark of DAY-GLO Fluorescent Pigment Signal Green A-18. Thismaterial comprises about 96 percent by weight of a thermoplasticmelamine-sulfonamidc-formaldehyde resin prepared in accordance withExample 1, about 3 percent by weight of a daylight fluorescent green dyeand about 1 percent by weight of a phthalocyanine green toner. Thismaterial has a minimum luminance factor of 55 percent, a minimum purityof 65 percent and a dominant wavelength of 540 to 547 millimicrons ornanometers determined in accordance with the daylight fluorescent colorspecification system described on pages 23 through 25 of the Day GloColor Corp. Technical Booklet No. 1170-A.

5 Marketed by El. du Pont do Ncmours dz Co., Inc., Wihmngton, Del.,

U.S.A.

6 Marketed by Charles Pfizer & Co., New York, N.Y., U.S.A. under thetrade designation of M04232.

Each of the above solvented coating compositions were prepared by mixingthe polysiloxane rubber gum, the poly siloxane resin and the toluene ina 500 ml. Erlenmeyer flask with constant stirring, thereby forming acomposition having a uniform consistency. Themelamine-sulfonamideformaldehyde resin and the sensible material werethen added to the composition with constant stirring, thereby forming acoating composition having a uniform consistency. The coatingcomposition was then ball milled in a 150 ml. stainless steel containercontaining 40 ml. of inch stainless steel balls until the particle sizeof the mclarnine-sulfonamide-formaldehyde resin was about 3 microns.Milling was performed on a paint shaker.

Each solvented coating composition was then coated onto a 0.35 milpolyethylene terephthalate film and was uniformly spread over the filmusing a wire wound rod to a coverage of about 18 milligrams of solventedcoating composition per square inch of film. The toluene was allowed toevaporate at room temperature thereby leaving a dried transferablecoating composition having a thickness of about 0.2 to 0.3 mil on thefilm. A thin film of a paraflin wax having a melting point of 156 F. anda needle penetration of 9 was then coated over the dried transferablecoating composition by means of a roller coating from a hot melt of thewax at a temperature of 208 F. The coated film was then cut intoprinting ribbons.

The green and black printing ribbons were then placed in an NCR ClassColor Bar Code System Tag and Label Printer manufactured by The NationalCash Register Company, Dayton, Ohio, USA. The Tag and Label Printerprinted a sequence of green and black bars on white paper labels. Theprinted bars were heat set on the surface of the receiving medium at atemperature of 320 F. for 0.5 second by means of a heated forced airblower. These green and black printed bars contain binary bits ofencoded information that are read by an optical detection system whereinthe spectral properties of the green and black printed bars and thewhite spaces of the paper label between the colored bars activate asensing device. The sensing device is activated by passing an opticalprobe tip over the printed bars; therefore, the printed bars mustpossess a clear edge definition and have a high resistance to scratchingand smudging in order for the encoded information contained in the barsto be properly read. Such a printing and optical scanning system isdisclosed in US. patent applications Ser. No. 837,514 filed June 30,1969, and Ser. No. 837,850 filed June 30, 1969.

The green and black bars printed on the labels were tested forresistance to scratching and smudging using a Gardner Laboratory ScratchTester. A standard color bar code system probe tip used in the opticalsystem under 500 grams of weight and perpendicular to the plane of theprinted bars was contacted with and passed over the printed bars tentimes. The standard probe tip was a color bar code system optical probetip. The printed bars possessed excellent resistance to scratching andsmudging upon visual examination. The optical probe tip was then passedover the printed bars and there was only a slight decrease in thereadability of the encoded information by the optical detection system.

In this example, the printed black bars had a diffused reflectance ofless than 15 percent of light between a wavelength of 600 to 1200nanometers and the printed green bars had a diffused reflectance of lessthan 15 percent of light between a wavelength of 600 and 750 nanometers,50 percent of light between a wavelength of about 820 and 870 nanometersand greater than percent of light between a wavelength of 900 and 1200nanometers. The white paper label had a diffused reflectance of morethan 80 percent of light between a wavelength of 600 and 1200nanometers.

Example 3 Green and black transfer media, that is, printing ribbons,were prepared in accordance with the procedures set forth in Example 2,using solventcd coating compositions described below.

SOLVENTED COATING COMPOSITIONS Parts by Weight oi Green Black Componentcomposition composition Polysiloxane rubber gum-SE46 1 8. 3 8. 3Polysiloxane resin-D C-2106 2 7. 7 7. 7Melamine-sulfonamide-for'maldehyde resin l7. 0 15. 0 Monastral green Bphthalocyanine polychloro copper toner-Color Index N 0.

74200 5 3. 0 Black magnetic iron oxide-MO4232 5. 0 Toluene 64. 0 64. 0

Total 100. 0

See footnotes and -Example 2.

7 Marketed by Day-G10 Color Corp., Cleveland, Ohio, U.S.A. under thetrademark of Sulfonamel. This resin is prepared in accordance withExample 1 and U.S. Pat. 2,809,954, Examples 1 through 6, and 11.8. Pat.2,938,873, Examples 1 through 6.

Example 4 A black, magnetic transfer media, that is, a printing ribbon,was prepared in accordance with the procedures set forth in Example 2using a solvented coating composition described below.

SOLVENTED COATING COMPOSITION Component: Parts by weight Polysiloxanerubber gumSE-76 1 8.3 Polysiloxane resin-DC-2106 2 7.7

Melamine-sulfonamide-formaldehyde resin 14.0

See footnotes 2 and Example 2.

See footnote "'Example 3.

Twenty-four (24) pound safety paper (17 in. x 22 in. x 500 sheets) whichis a commonly used paper for bank checks was encoded on a C-481 Encoder,manufactured by The National Cash Register Company, Dayton, Ohio,U.S.A., using the black, magnetic printing ribbon prepared in thisexample.

After the transferable coating composition was encoded or printed on thesafety paper, the encoded safety paper was electronically scanned usingcalibrated measuring equipment comprising a Whirly Sig Mark II MagneticInk Tester, manufactured by Kidder Press Company, Dover, N. H., U.S.A.connected to a Tektronix 564 Storage Oscilloscope, manufactured byTektronix Incorporated, Beaverton, reg., U.S.A., to determine thedynamic signal level of the encoded or printed characters on the safetypaper and to establish a control on the nominal signal of one of thebase characters. The signal level measuring instrument was calibratedusing a secondary signal level reference document obtained from the BankAdministration Institute, Park Ridge, 111., U.S.A. The signal level asused herein is defined as the amplitude of the voltage waveform producedwhen a direct current magnetized printed character is scanned by asuitable magnetic reading head.

The signal level of the electronically scanned encoded safety paper wasof good quality and the signal waveforms were clean and free fromextraneous signals of residual magnetic ink particles.

The example illustrates that the sensible material can be selected froma variety of sensible materials for use in MICR, OCR or even one-timetypewriter ribbons.

It is claimed:

1. A transfer medium comprising a base having a transferable coatingcomposition thereon said coating composition comprising about 3 to 40percent by weight of a polysiloxane rubber gum having a molecular weightranging from about 200,000 to 1,000,000; about 3 to 40 percent by weightof a polysiloxane resin having a molecular weight ranging from about 300to 100,000; about 15 to 70 percent by weight of a thermoplasticaminotriazinesulfonamide-aldehyde resin said resin comprising thecondensation product of at least one aldehyde selected from the groupconsisting of formaldehyde and paraformaldehyde, at least one aromaticmonosulfonamide having two reactive amide hydrogens where thesulfonamido group is attached directly to the aromatic nucleus throughthe sulfur atom, and at least one aminotriazine having at least twoamino groups, the amount of said aminotriazine being between about 17and 50 mole percent of said monosulfonamide and the total amount of saidaldehyde constituent being at least in excess of the total amount ofsaid sulfonamide and aminotriazine constitutes on a molar basis; andabout 1 to percent by weight of a sensible material, the outer surfaceof the coating composition having a thin coating of wax to aid inadherence of the coating composition to a receiving medium wherein theaminotriazine resin has a particle size of about 3 microns and is atmost only partially soluble in a volatile organic solvent, and thetransferable coating composition has a thickness of about 0.1 to 0.4mil.

2. The transfer medium of claim 1 wherein the polysiloxane rubber gumhas a molecular weight ranging from about 300,000 to 700,000 and ispresent in the coating composition in an amount of about 15 to 25percent by weight.

3. The transfer medium of claim 1 wherein the polysiloxane resin ispresent in the coating composition in an amount of about 10 to 25percent by weight.

4. The transfer medium of claim 1 wherein the aminotriazine component ofthe thermoplastic resin is melamine and said resin is present in thecoating composition in an amount of about to percent by weight.

5. The transfer medium of claim 1 wherein said sensible materialcomprises a green dye or pigment.

6. The transfer medium of claim 1 wherein said sensible materialcomprises a red dye or pigment.

7. The transfer medium of claim 1 wherein said sensible materialcomprises a black dye or pigment.

8. The transfer medium of claim 1 wherein said sensible materialcomprises a magnetic metal or oxide thereof.

9. The transfer medium of claim 1 wherein said sensible material isinvisible to the naked eye under ordinary light.

10. The transfer medium of claim 1 wherein the sensible material ispresent in the coating composition in an amount of about 2 to 20 percentby weight.

11. The transfer medium of claim 1 wherein said base is a thin material.

12. The transfer medium of claim 11 wherein said base is a polymericmaterial.

13. The transfer medium of claim 12 wherein said base is a film ofpolyethylene terephthalate.

References Cited UNITED STATES PATENTS 3,087,832 4/1963 Fogle ll736.43,519,464 7/1970 Balster et a1. 11736.1

MURRAY KATZ, Primary Examiner US. Cl. X.R.

1l7-36.l, 138.8 F, L; 260-39 P, 824

